Not during TT! 
They seem to be trying to sort out the 'spring' of water, that keeps coming out of the road just after Glen Helen. 
Mind you, I think they did try in July last year too!
Read about the plan here -
https://www.bbc.co.uk/news/articles/c9811w0x25do

Needs sorting, it ranges from a dark patch to a serious flow and depending on where it's rained the water can be random in appearance and speed of appearance. .... similar happens at Ramsey Hairpin but not as wet.